Social emotional development in early childhood serves as the foundation for mental health across the lifespan. Results from a recent nationally-representative study of U.S. kindergarteners show a clear difference in social emotional development by race/ethnicity, with greater percentages of minority children compared to white children entering school with fewer social emotional competencies. These disparities in children's early mental health are particularly concerning given the growing number of minority children in the U.S., coupled with evidence that early social emotional deficits have short-term implications for school readiness and longer- term implications including lower occupational attainment, higher rates of teen pregnancy and depression. While studies have documented racial/ethnic disparities in social emotional development upon children's entry to school, there have been no studies examining racial/ethnic differences in a contemporary, nationally representative sample of children in early childhood and the factors that may account for these disparities. The three specific aims of the proposed study are: 1) examine the extent of racial/ethnic differences in children's social emotional development at 2 years of age;2) determine whether differences in child characteristics, family demographic characteristics, family context and child care context explain racial/ethnic variation in children's social emotional development at 2 years of age;and 3) determine whether relations among child characteristics, family demographic characteristics, family context, child care context and children's social emotional development vary by race/ethnicity at 2 years of age. Data are from the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B) funded by the U.S. Department of Education in collaboration with the National Institute of Mental Health (NIMH).The ECLS-B follows a nationally representative sample of approximately 14,000 children born in 2001. Data include direct measures of social emotional development at 2 years of age and additional measures of parent and child characteristics at 9 months. Regression models will be constructed to examine the direct and indirect relationship between child's race/ethnicity and social emotional outcomes. The proposed dissertation project is highly relevant to NIMH's mission to reduce the burden of mental illness and behavioral disorders through research on mind, brain, and behavior and address the Division of Pediatric Translational Research and Treatment Development's high priority area delineating mechanisms and processes of neurobehavioral development relevant to understanding pediatric mental disorders with a focus on periods of rapid neurobiological change (e.g., infancy, preschool, adolescent periods), during which the brain is particularly sensitive to contextual influence . Assessing the contribution of factors impacting social emotional development at two years and the pathways by which they operate can provide evidence regarding opportunities for early intervention aimed at reducing disparities in children's mental health.